Wearable Motion Assist Evaluation for Hip Torque and Joint Range

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Solution Overview

Problem

There is a lack of objective standards and efficient methods to evaluate the performance of wearable motion assistance devices, particularly in assessing the assist force on knee and hip joints and the adduction/abduction range of motion for lower back assistance, making it cumbersome and complicated to construct a performance evaluation apparatus.

Innovation Solution

A performance evaluation apparatus with a base, driving sources, torque detecting units, and a control unit that secures the wearable motion assistance device to the wearer's femur and trunk links, allowing for the evaluation of assist force, braking force, and adduction/abduction range of motion by simulating the wearer's motions and detecting torque, force, and rotation angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a performance evaluation apparatus is constructed to evaluate both assist force for bending/extending leg joints and adduction/abduction range of motion of hip joints using separate apparatuses, then measurement precision is improved, but device complexity increases and evaluation efficiency decreases

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple evaluation functions (assist force measurement for knee joints, assist force measurement for hip joints, and adduction/abduction range of motion measurement) into a single integrated performance evaluation apparatus. The base unit houses multiple driving sources that can independently control different joint movements, allowing comprehensive evaluation without requiring multiple separate apparatuses, thus reducing device complexity while maintaining measurement precision

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The base unit is designed with multiple driving sources (first driving source for knee joints, second driving source for hip joints) that can perform multiple evaluation functions simultaneously or sequentially. This universal design allows the same apparatus to evaluate different aspects of wearable motion assistance device performance, improving evaluation efficiency while maintaining comprehensive measurement capabilities

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If driving force is transmitted to both knee joint and hip joint from the same driving source, then device complexity is reduced, but transmission errors increase and measurement precision deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidtransmission error
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the driving force transmission system by providing separate driving sources for different joint evaluations. The first driving source is dedicated to transmitting driving force to knee joints, while the second driving source is dedicated to transmitting driving force to hip joints. This segmentation eliminates transmission errors that would occur if a single driving source had to serve multiple joint types, while the modular base unit design keeps overall device complexity manageable

Inventive Principle:
Principle #1Segmentation

3Productivity

If multiple driving sources are used to evaluate different joint movements simultaneously, then evaluation efficiency is improved, but device complexity and cost increase

Engineering Contradiction:
Improveevaluation efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges multiple driving sources into a single integrated base unit that houses both the first driving source (for knee joints) and the second driving source (for hip joints). This consolidation allows simultaneous or sequential evaluation of different joint movements without requiring multiple separate apparatuses, improving evaluation efficiency while keeping device complexity manageable through unified design

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables efficient evaluation of assist force, braking force, and adduction/abduction range of motion for wearable motion assistance devices, reducing transmission errors and preventing defects, while estimating the load applied to the wearer's lower back, thus providing a comprehensive performance assessment.

Implementation Method 1

a torque detecting unit that detects torque acting on an axis line of the pitch direction relative to the trunk link for each hip joint

Methodology Applied
Scientific EffectTorque detection: Torque

Data Source

PatentEP3395512B1Wearable motion assisting device, performance evaluation device and performance evaluation method
Publication Date: 2021.07.28 CYBERDYNE INC
  • EP3395512B1 patent drawingFigure 1(A)~1(C)
  • EP3395512B1 patent drawingFigure 2(A)~2(C)
  • EP3395512B1 patent drawingFigure 3(A)~3(C)

AI summary

The present invention was devised in consideration of the above-described circumstances and provides a performance evaluation apparatus and performance evaluation method capable of efficiently evaluating the performance of a wearable motion assistance device, which assists motions of a wearer's lower back part, by using a comparatively simple configuration. In a state where the wearable motion assistance device is secured and mounted on both femur links and a trunk link, torque acting on an axis line of a pitch direction relative to the trunk link for each hip joint is detected while controlling driving forces by first and second driving sources so that a posture of the trunk link and rotation angles of each hip joint and each knee joint virtually match motions of the lower back part of the wearer; and performance of an assist force by the wearable motion assistance device is evaluated on the basis of a detection result of the torque according to drive control of the first and second driving sources.